VulnerabilityPublished 3 Jun 2025

CVE-2025-30360: webpack-dev-server · Origin Validation Error

Affects webpack-dev-serverSource CVE Database V5

Mentioned vulnerabilities

CVE-2018-14732

Not known to be exploited · CVSS 6.5 Medium : upgrade to 5.2.1 when convenient.

Data as of 26 Oct 2026, 11:42 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.2.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 3 Jun 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade webpack-dev-server to 5.2.1.

Affected software

Product	Affected	Fixed in
npmwebpack-dev-server`pkg:npm/webpack-dev-server`Other threats	Affected <5.2.1	Fixed in 5.2.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

European organizations should immediately upgrade all instances of webpack-dev-server to version 5.2.1 or later to apply the official patch that correctly validates Origin headers, including those with IP addresses. Development teams should audit their environments to identify any use of vulnerable versions and enforce upgrade policies. Additionally, developers should be advised to avoid visiting untrusted or malicious websites while running development servers locally. Network segmentation can be employed to isolate development environments from general internet access where feasible. Implementing browser security policies or extensions that restrict WebSocket connections from untrusted origins can provide an additional layer of defense. Monitoring WebSocket traffic for unusual connections may help detect exploitation attempts. Finally, organizations should educate developers about the risks of cross-site WebSocket hijacking and encourage the use of Chromium-based browsers when possible, as the vulnerability specifically affects non-Chromium browsers.

Description

webpack-dev-server allows users to use webpack with a development server that provides live reloading. Prior to version 5.2.1, webpack-dev-server users' source code may be stolen when you access a malicious web site with non-Chromium based browser. The `Origin` header is checked to prevent Cross-site WebSocket hijacking from happening, which was reported by CVE-2018-14732. But webpack-dev-server always allows IP address `Origin` headers. This allows websites that are served on IP addresses to connect WebSocket. An attacker can obtain source code via a method similar to that used to exploit CVE-2018-14732. Version 5.2.1 contains a patch for the issue.

Impact

For European organizations, this vulnerability poses a significant risk primarily to developers and development environments using webpack-dev-server versions prior to 5.2.1. The exposure of source code can lead to intellectual property theft, leakage of sensitive business logic, and potential facilitation of further attacks such as code injection or supply chain compromise. Since webpack-dev-server is typically used in local or internal development environments, the risk is mostly to internal confidentiality rather than public-facing systems. However, organizations with remote or hybrid development setups, or those allowing developers to browse untrusted websites while running vulnerable versions, are at higher risk. The impact is heightened in sectors with strong intellectual property concerns such as software development firms, financial services, and technology companies prevalent in Europe. Additionally, the use of non-Chromium browsers (e.g., Firefox, Safari) increases susceptibility, which is relevant given diverse browser usage in Europe. While no integrity or availability impact is noted, the confidentiality breach can have downstream consequences including reputational damage and regulatory scrutiny under GDPR if sensitive data is exposed.

CWE-346Origin Validation Error (opens in a new tab)
Class weaknessOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product does not properly verify that the source of data or communication is valid.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V14.5.2 (opens in a new tab)
V14.5.3 (opens in a new tab)
V1.4.4 (opens in a new tab)
Attack patterns
JSON Hijacking (aka JavaScript Hijacking) (opens in a new tab)
Cache Poisoning (opens in a new tab)
DNS Cache Poisoning (opens in a new tab)
Exploit Script-Based APIs (opens in a new tab)
Application API Message Manipulation via Man-in-the-Middle (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Jul 2025, 06:17 UTC

WeaknessesCWE-346

Technical details

References

Community reviews

Related threats